where the arrows FF in the top view represent the forces with which the bearings must act upon the engine shaft to produce the torque T.
Gyrostatic Action of a Rolling Disk
Fig. 23 represents a penny rolling along a floor. The forces FF in the side view (the tendency of the penny to fall over) constitute a torque which is represented by the arrow T in the top view. This torque produces during a short interval of time an increment of spin-momentum